Electric heater.



E. THOMSON. ELECTRIC HEATER.

APPLICATION FILED FEB. 16, 1912,

1,072,530. Patented sept.9,1913.

2 SHEETS-SHEET 1.

mgl.

E. THOMSON.

ELECTRIC HEATER.

APPLIGATION FILED PEB. 1e, 1912.

1 ,072,530, l Patented Sept. 9, 1913.

2 SHEETS-SHEET Z.

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Inventor:

. 'UNITED sTATEs PATENT oFF-ion.

ELIHU THOMSON, E sWAMPsooczr, MASSACHUSETTS, AssIGNon To GENERAL ELBoTnmCOMPANY, A CoRronATIoN I.inraEcTnic HEATER.

To all whom t may ooncem:

Be it known that I, Erano THOMSON, a

i citizen of the United States, residing at Swampscott, county ofEssex,` State of Massachusetts, have invented certain new and usefulImprovements in Electric Heaters, of which the following is aspecificati-on.

My invention relates to electricI heating devices, and more particularlyto such electric heating devices ss comprise meansV for storing heattherein and for liberating the same when desired.

One of the objectsy of my invent-ion is to provide a device of thischaracter having a simple and inexpensive electric heating means whichwill 'possess a greater degree of regulability than that possessed byordinary heating units. I attain this object b the use of an electricarc in connection wit the heat storage mass. I prefer to have thestorage mass` constitute one electrode of the arc as by such arrangementthe heat is very eiciently and rapidly stored.

Another object of my invention is to provide means for varying the4amount of energy supplied to an electricheater according to thetemperature of the same. I attain this object by the use in connectionwith4 a movable member, the position of' which deterrnines the energysupplied to the heater, of coils exerting different attractive effectson the said movable member and an arrangement whereby thev relativel'es'istances of the respective coils, and therefore the relativecurrents passing therethrough, are changed by variations in temperatureoi the heating device.

My invention will be better understood by reference to the drawings inwhich it is shown embodied in several specific forms.

In the` drawings, Fi 1 is' a vertical section of one form o heat storagestove embodying my invention; Fig. 2 is a similar view of a modicatio'nof the-same; Figs. 3, 'lando are partial sections of stoves having meansfor automatically'rc lating the current supplied to the are; an Figs. 6,7,

8, 9 and IO are diagrams showing the circuits for the Adevices shownnFigs. 1, 2, 3, 4 and respectively. i The stove chown in the drawingcomprises u heating chamber haring inner and outer j sitmn and 'amount`an arc of a certain current strength orxcng walls i and 2, which maybeof metal, and lagging 3 which-may be asbestos or any Specification ofLetters Patent.

' Application filed February 16, 1912. Serial No.

0F NEW YORK.-

' ratenteasept. 9, 191s: 678,121.

other good heat insulating material between the said walls. Thev top yofthe heating chamber is formed 4 which may be of iron, steel or anymaterial having comparatively high specific heat, high specific gravityand high specific heat conductivity. The heat storage mass l issupported by the walls of the heating chamby the heat storage massberlfrom which it is separated by insulation 5, which may be of mica, or anyother substance having good electrical and heat insu-l latingproperties. A cover 6- consisting of a hollow shell of. thin sheet metalfilled with insulation 7 which may be similar to lagging 3 is providedtor the'heat storage mass. A Water jacket 8, as shown in Fig. 1, maysurround the outer wall of the heating chamA ber so thatany heat which'may be conducted through the insulating walls of the said chamber may beutilized. The pipe connections 8 and S2 are provided for supplying Waterto and conducting the same vfrom the Water jacket.' The supply terminal9 is at! tached to the heat storage mass and projects through the Wallsvci the surrounding vessel.

In theflevice shown in Fig. fx1, the ysolenoid 10 is' mounted on thebottom of theheatin'g chamber. The solenoid coil used in this' form'ofmy invention is preferably a fire-V proof edgewise winding or'otherstructure capable of withstanding high temperature and having asufcientdrop to cause'steadiness in the are. The are is vformed between thestorage mass 4 and the electrode 11 whichfin this case also acts as acore for the solenoid 10 and is therefore of iron or other magneticmaterial as shown in Fig. 1, or the electrode may be of carbon or thelike and he supported by a holder 12 which may be the core of thesolenoid and therefore be of magnetic material, as shown in Fig. 2. Thiselectrode is counterbalancexl by the Weight 13 mounted upon one end ofthe lever 14 which is pivoted on the solenoid frame. Tor the other endof this lever is connected the core 11 by means of the rod I5. One endof the solenoid windin is connected to the terminal 16y which projectsthrough the walls of the stove and the other end is attached to thecase. l/Vhen a snitlable current is supplied to the apparatus,

the solenoid magnet is adjusted by the poof the weight 13 to draw whichinvolves the delivery of a certain amount of electrical energy. Onaccount of the walls of the heatingchamber being an excellentnon-conductor of heat most of the 5 heat finds its Way into thestorage-mass 4 and raises its temperature so that after aconipartivelyshort time,- say an hour or two, it is ready to be used. Byremoving the cover 6, a sauce pan or other cooking vessel or anythingwhich. it is desired to heat may be placed therein and heatl will becommunicated very rapidly to it owing tov the high conductivity of thestorage mass. After the heating operation is completed *the cover 6 maybe again placed upon the st orage'mass and the temperature will againrisedue to the heat delivered to the mass by theelectric arc. Owing tothe provision of good heat yinsulationl around the'storage mass it willretain its heat for along time after the current is cut oit from it.

In Fig. 2 I have shown a modification in which the coil 10A is locatedoutside of the heating chamber, the core 11 projecting into the same.This, arrangement allows the space between the bottom of the storagemass and the bottom of the heating chamber `to .be lessened,` thusdecreasing the radiating surface of theheating chamber. Inthismodification the lcoil owing tofits locationneed not be of heatresisting material but may be wound with ordinary insulated Wire. Aregulable spring 17 supported upon the bracket 18 attached to thesolenoid may be used to .regulate the length of the arc and thusdetermine the amount of energy normally supplied thereto. A steadyingresistance 19 consisting of a flat coil withits turns open and separatedfrom the bottom of the heating chamber by suitable electrical insulation20 may be used. vThis resistance may have a drop of from 20 to 30 voltson a 110 volt circuit for steadying the arc. The resistance 19, theregulating coil '10 and the storage mass 4 are preferably in series asshown in Fig. 7 In this modification the action of the apparatus may beobserved from the outside vand adjustment' may be made for diiferentcurrent strengths in the heating arc. y

In Figs. 8,4 and 5 I have shownl thermoelectric regulating means forthearc. In Fig. 3 the upper coil 21 is of iron or any metalwhose'resistance has a high positive temperature cociicient while thelower coil 22 is of German silver or any metal whose resistance has acomparatively'low temperature coefficient. The magnetizable core 11 isso' located with respect to the coils 2.1 and 22 that a given currentexerts a greater pull in the lower-coil 22 than'in the upper coil 21.`Aas-,shown in the diagram constituting Fig. 8, the current divides atterminal 16, part 'of -it going through thel upper coil' and part of itthroughthe lower coil. These circuits then unite at the core 11 betweenwhich and the mass 4 the arc formed. When a. high temperature 1s reachedin the heating chamber, more current is shunted through -theflower coilthan .through theuper coil owing to the increased eating the lower coil22 outside'of the heatving chamber and the upper coil 2 1 within thesame, as shown 1n Fig. .4, the same regulation may be secured and 1nsuch -an arrangement it is not necessary to have the '85 `coils ofdifferent metals'. They can both be of iron, for example, or one of ironand the other or'copper. In suchan arrangement the current would' beshunted from the hot-` ter to the'` cooler coil.

In Fig. 5 I have shown an arrangement in'whi'ch the coils 23 and 24 forcontrolling the length of the arc are located outside of the heatingchamber. In this arrangement, the steadying resistance 19 .is alsoshown. As shown in Fig 10 the current after leav-l ing the terminal 16divides, one portion passing through the steadying resistance 19 and theother through the outer coil 24.- These circuits then unite and thecurrent then passes through the innercoil-23, the

vcore l1 and the storage mass 4. The resist- .ance 19. 1s of va materialsuch as iron having va high temperature coefficient, and when it reachesa high temperature more current is shunted to the supplemental coil 24which acts in conjunctionwith the coil 23 toextend the arc, therebyweakening thecurrent and .reducing the delivery of energy.

Various modifications of the structure disclosed will readily suggestthemselvesto those skilled in the art, and the same may be made withoutdeparting from the-spirit of my invention, the scope of which is setforthv in theannexed claims.

What I claim as new and desire to secure by Letters Patent of the IInitedStates,l is,-

1. An electric heater comprising a heat stora emas's, meansfor'producing an electricv arcor heating the same, and means for 12oconning the heat generated by the arc t the storage mass. v v

2. An electric heater comprising a'heatl storage mass having good heatconductivity and constitutinga wall of c heating cham- 125 ber, heatinsulating means constituting the remaining walls of the said chamber,and means for producing'an electric arc within the saidchamber515011,heatingA the said stolz... agemass.

, tric arc for heating thesame, and means for automatically controllingthe supply of energy to the arc according to the temperature of thestorage mass.

5. A heater comprising a heat storage mass, 'man electrode adjacentthereto, means for producing an electricv arc between the "saidelectrode and the said heat storage mass, and means controlled by thetemperature of the storage mass for regulating the amount of energysupplied to the arc.

6. In a heater, a storage massjforming one Wall lof, a heating chamber,insulation forming the other Walls, an electrode so disposed thatanelectric arc may be drawn between it and the storage'mass within theheating chamber, and means controlled by the temperature of the heatingchamber for regulating the amount of energy supplied to said arc.

7. In an electric heater, the combination of a heat storage mass, meansfor producing an electric arc for heating the same including a movableelectrode, electro-magnetic means for controlling the position of thesaid electrode, and means for varying the 1 Copies of this patent may beobtained effect-.of said electro-magnetic means according to thetemperature" of the storage mass. 8. An electric heater comprising aheat storage mass connected to one side ofen electric circuit, anelectrode associated therewith so as to draw an arc between the mass andthe electrode, and means' forl conning y the heat developed by the arcto the storage 9. Ina heating device, means for producing heat by theconsumption of electric energy comprising a movable element, and

means for controlling the amount of energy supplied to said heatproducing means by varying the positionv of said movable elementcomprismg a plurality of coils ,exerting diiierent attractive effectsthereon and means for controlling the current passing through therespectivecoils according tothe temperature produced by the heatingmeans. 10.In .a heating device, a movable member, the position .of whichdetermines the amount of energy supplied to the device, and -acontrolling Adevice for said movable member comprising coils havingdifferent attractive effect on the movable member, the resistance ofcertain of said coils being i'ncreased relative to each other by anincrease in temperature of the heating device.

In Witness-whereof, I have hereunto set my hand this thirteenth day ofFebruary,

ELIHU THOMSON.

Witnesses:

JOHN A. MCMANUS, Jr., FRANK G. I-IA'rrIE.

